J. Edgar Hoover

J. Edgar Hoover began using wiretapping in the 1920s during Prohibition to arrest bootleggers.[13] A 1927 case in which a bootlegger was caught through telephone tapping went to the United States Supreme Court, which ruled that the FBI could use wiretaps in its investigations and did not violate the Fourth Amendment as unlawful search and seizure as long as the FBI did not break in to a person's home to complete the tapping.[13] After Prohibition's repeal, Congress passed the 1934 Communications Act, which outlawed non-consensual phone tapping, but allowed bugging.[13] In another Supreme Court case, the court ruled in 1939 that due to the 1934 law, evidence the FBI obtained by phone tapping was inadmissible in court.[13] A 1967 Supreme Court decision overturned the 1927 case allowing bugging, after which Congress passed the Omnibus Crime Control and Safe Streets Act, allowing public authorities to tap telephones during investigations, as long as they obtain a warrant beforehand.[13]